pub fn odd_fibnacci_sum(threshold: u32) -> u32 {
    if threshold == 1{
        return 2;
    }
    let mut sum = 1;
    let (mut a, mut b) = (1, 1); // 初始化前两个斐波那契数字
    while b < threshold {
        if b % 2 == 1 {
            sum += b;
        }
        let next = a + b;
        a = b;
        b = next;
    }
    sum

}
